IS-GPS-800A - US Coast Guard Navigation Center

Carriers of the two L1C components shall be in the same phase (within ±100 milliradians) as the P(Y)-code carrier.See IS-GPS-200 for phase relationships to other L1 signals.3.2.1.6.2 Phase ContinuityWhile a satellite is broadcasting standard L1C P code and standard L1C D code signals with data which indicates L1Csignal health is OK, there will not be any commanded operation causing an intentional phase discontinuity. Thisdoes not apply to phase discontinuities caused by signal modulation. Phase discontinuities are subject to therequirements of 3.2.1.6.1.3.2.1.7 Signal Characteristics3.2.1.7.1 Signal CoherenceAll transmitted signals for a particular SV shall be coherently derived from the same on-board frequency standard.On the L1 carrier, the chip transitions of the two modulating signals, L1C D and L1C P , shall be such that the averagetime difference between them (i.e. L1C D /L1C P ), and between each and the transitions of L1P(Y) (i.e. L1C D /L1P(Y),L1C P /L1P(Y)), do not exceed 10 nanoseconds. The variable time difference shall not exceed 1 nanosecond (95%probability), when including consideration of the temperature and antenna effect changes during a vehicle orbitalrevolution. Corrections for the bias components of the time difference are provided to the US in the CNAV-2message using parameters designated as ISCs (reference paragraph 3.5.3.9.1).3.2.1.7.2 Signal DistortionThe duration of the “+1 polarity” portions of the BOC (1, 1) code shall equal the duration of the “-1 polarity”portions of the BOC (1, 1) code within 5 nanoseconds as measured at the zero crossing point.The duration of the “+1 polarity” portions of the BOC (6, 1) code shall equal the duration of the “-1 polarity”portions of the BOC (6, 1) code within 5 nanoseconds as measured at the zero crossing point.3.2.1.8 Equipment Group DelayEquipment group delay is defined as the delay between the signal radiated output of a specific SV (measured at theantenna phase center as observed from the signal’s zero crossings) and the output of that SV's on-board frequencysource; the delay consists of a bias term and an uncertainty. The bias term is of no concern to the US since it isincluded in the clock correction parameters relayed in the navigation data, and is therefore accounted for by the usercomputations of system time. The uncertainty (variation) of this delay, as well as the group delay differential,between the reference signal and the signals of L1C, are defined in the following subsections.3.2.1.8.1 Group Delay UncertaintyThe effective uncertainty of the group delay shall not exceed 1.5 nanoseconds (95% probability).5 IS-GPS-800A8 June 2010